io-adapters: add support for BufRead for `futures` and `tokio`. #940

Job	Run time
test (stable, x86_64-unknown-linux-gnu)	43s
test (stable, thumbv7m-none-eabi)	22s
test (1.60.0, x86_64-unknown-linux-gnu)	2m 29s
test (1.60.0, thumbv7m-none-eabi)	2m 32s
test (nightly, x86_64-unknown-linux-gnu)	31s
test (nightly, thumbv7m-none-eabi)	15s
test (stable, x86_64-unknown-linux-gnu, std)	30s
test (stable, x86_64-unknown-linux-gnu, alloc)	37s
test (nightly, x86_64-unknown-linux-gnu, std,tokio-1,futures-03,defmt-03)	41s
	8m 40s

Provide feedback